Composition and method for a hexadentate ligand and bimetallic complex for polymerization of olefins

ABSTRACT

A hexadentate ligand for polymerization of olefins including chemical structure I is provided:  
                 
 
     R1, R2, and R3 of chemical structure I are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functional group; R4 and R5 are each independently hydrogen, hydrocarbyl, an inert functional group, or substituted hydrocarbyl; Y1 is a structural bridge; and W, Y1, and Z are independently hydrogen, hydrocarbyl, an inert functional group, or substituted hydrocarbyl having from about 0 to about 30 carbon atoms. In another embodiment of chemical structure I, W, Y 1 , and Z are selected to produce chemical structure II:  
                 
 
     R 6 , R 7 , R 8 , R 9 , and R 10  of chemical structure II are each independently hydrogen, hydrocarbyl, an inert functional group, or substituted hydrocarbyl; R A , R B , R C , and R D  are each independently hydrogen, fluorine, an inert functional group, a primary carbon group, a secondary carbon group, or a tertiary carbon group; Y 2  is a structural bridge between two halves of the structure, and more particularly may be a bond, a hydrocarbyl group comprising from about 0 to about 20 carbon atoms, methylene (CH 2 ), ethylene (C 2 H 4 ), or an inert functional group; and any two of R A , R 6 , R 7 , R B , R C , R 8 , R 9 , R 10 , and R D , or any portion of Y 2 , vicinal to one another, taken together may form a ring.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] None.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

[0003] Not applicable.

FIELD OF THE INVENTION

[0004] The present application relates generally to olefinoligomerization. More particularly, the present application relates to anovel hexadentate ligand, associated hexadentate bimetallic complex, andmethods of making such hexadentate ligands and complexes. Additionally,the hexadentate ligand and complex are employed in the oligomerizationof olefins.

BACKGROUND OF THE INVENTION

[0005] Olefins, also commonly known as alkenes, are important items ofcommerce. Their many applications include employment as intermediates inthe manufacture of detergents, as more environmentally friendlyreplacements where refined oils might otherwise be used, as monomers,and as intermediates for many other types of products. An importantsubset of olefins are olefin oligomers, and one method of making olefinoligomers is via oligomerization of ethylene, which is a catalyticreaction involving various types of catalysts. Examples of catalystsused commercially in polymerization and oligomerization of olefinsinclude alkylaluminum compounds, certain nickel-phosphine complexes, anda titanium halide with a Lewis acid, such as diethylaluminum chloride.

[0006] Another group of olefin polymerization catalysts is derived frompyridine bisimines. With catalysts of this type, a nitrogen-based ligandengages in a coordination reaction with a transition metal salt. Thecoordination reaction forms a metal complex, which is a catalystprecursor. The metal complex further reacts with another precursor oractivator to generate a metal alkyl or metal hydride species. Thecatalyst resulting from the generation of the metal alkyl or metalhydride species polymerizes olefins.

[0007] Applications and demand for olefin polymers and oligomerscontinue to multiply, and competition to supply them correspondinglyintensifies. Thus, additional novel and improved catalysts and methodsfor olefin polymerization and oligomerization are desirable.

SUMMARY OF THE INVENTION

[0008] A hexadentate ligand for polymerization of olefins includingchemical structure I is provided:

[0009] R₁, R₂, and R₃ of chemical structure I are each independentlyhydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functionalgroup; R₄ and R₅ are each independently hydrogen, hydrocarbyl, an inertfunctional group, or substituted hydrocarbyl; Y₁ is a structural bridge;and W, Y₁, and Z are independently hydrogen, hydrocarbyl, an inertfunctional group, or substituted hydrocarbyl having from about 0 toabout 30 carbon atoms. In an embodiment of chemical structure I, thegroups W, Y₁, and Z are selected such that an activated transition metalcomplex of the ligand, in the presence of one or more monomers undersuitable polymerization conditions, results in a polymerization producthaving greater than about 50 weight percent oligomers having from about4 to about 30 carbon atoms. In another embodiment, chemical structure Iincludes a mirror plane. In another embodiment of chemical structure I,the groups W, Y₁, and Z are selected to produce chemical structure II:

[0010] R₆, R₇, R₈, R₉, and R₁₀ of chemical structure II are eachindependently hydrogen, hydrocarbyl, an inert functional group, orsubstituted hydrocarbyl; R_(A), R_(B), R_(C), and R_(D) are eachindependently hydrogen, fluorine, an inert functional group, a primarycarbon group, a secondary carbon group, or a tertiary carbon group; Y₂is a structural bridge between two halves of the structure, and moreparticularly may be a bond, a hydrocarbyl group comprising from about 0to about 20 carbon atoms, methylene (CH₂), ethylene (C₂H₄), or an inertfunctional group; and any two of R_(A), R₆, R₇, R_(B), R_(C), R₈, R₉,R₁₀, and R_(D), or any portion of Y₂, vicinal to one another, takentogether may form a ring.

[0011] In another embodiment, a hexadentate bimetallic complex havingchemical structure III, and method of producing same, is provided:

[0012] R1, R2, R3, R4, R5, W, Z, and Y1 are as defined above forchemical structure I. M₁ and M₂ are metal atoms that may beindependently selected from the group consisting of cobalt, iron,chromium, and vanadium; each X may be an anion, such as a halide oracetyl acetonate, so that the total number of negative charges on X isequal to the oxidation state of M₁ or M₂; and n is 1, 2, or 3, so thatthe total number of negative charges on X is equal to the oxidationstate of M₁ or M₂.

[0013] In another embodiment, a hexadentate bimetallic complex havingchemical structure IV, and method of producing same, is provided:

[0014] The method for producing chemical structure IV includes mixing apyridine compound having chemical structure V:

[0015] with a substituted arylene diamine having chemical structure VI:

[0016] and a substituted aryl amine having chemical structure VII:

[0017] in a suitable solvent; and adding at least one metal salt of theformula MX_(n). R₁, R₂, and R₃ of chemical structure IV are eachindependently hydrogen, hydrocarbyl, substituted hydrocarbyl, or aninert functional group; R₄ and R₅ are each independently hydrogen,hydrocarbyl, an inert functional group, or substituted hydrocarbyl; R₆,R₇, R₈, R₉, and R₁₀ are each independently hydrogen, hydrocarbyl, aninert functional group, or substituted hydrocarbyl; R_(A), R_(B), R_(C),and R_(D) are each independently hydrogen, fluorine, an inert functionalgroup, a primary carbon group, a secondary carbon group, or a tertiarycarbon group; Y₂ is a structural bridge between two halves of thestructure, and more particularly may be a bond, a hydrocarbyl groupcomprising from about 0 to about 20 carbon atoms, methylene (CH₂),ethylene (C₂H₄), or an inert functional group; any two of R_(A), R₆, R₇,R_(B), R_(C), R₈, R₉, R₁₀, and R_(D), or any portion of Y₂, vicinal toone another, taken together may form a ring; M₁ and M₂ are independentlyselected metal atoms that are selected from a group comprising cobalt,iron, chromium, and vanadium; each X is an anion; and n is 1, 2, or 3,so that the total number of negative charges on X is equal to theoxidation state of M₁ or M₂.

[0018] In another embodiment, a method for preparing a polymerizationcatalyst system is provided. Such method includes executing acoordination reaction between a hexadentate ligand having chemicalstructure II:

[0019] and a metal salt of the formula MX_(n), to form a hexadentatebimetallic complex having chemical structure IV:

[0020] The method also includes generating a metal alkyl or metalhydride species; and contacting the catalyst system with one or moremonomers under suitable reaction conditions to polymerize the monomer.R₁, R₂, and R₃ of chemical structures II and IV are each independentlyhydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functionalgroup; R₄ and R₅ are each independently hydrogen, hydrocarbyl, an inertfunctional group, or substituted hydrocarbyl; R₆, R₇, R₈, R₉, and R₁₀are each independently hydrogen, hydrocarbyl, an inert functional group,or substituted hydrocarbyl; R_(A), R_(B), R_(C), and R_(D) are eachindependently hydrogen, fluorine, an inert functional group, a primarycarbon group, a secondary carbon group, or a tertiary carbon group; Y₂is a structural bridge between two halves of the structure, and moreparticularly may be a bond, a hydrocarbyl group comprising from about 0to about 20 carbon atoms, methylene (CH₂), ethylene (C₂H₄), or an inertfunctional group; any two of R_(A), R₆, R₇, R_(B), R_(C), R₈, R₉, R₁₀,and R_(D), or any portion of Y₂, vicinal to one another, taken togethermay form a ring; M₁ and M₂ are independently selected metal atoms thatare selected from a group comprising cobalt, iron, chromium, andvanadium; each X is an anion; n is 1, 2, or 3, so that the total numberof negative charges on X is equal to the oxidation state of M₁ or M₂;and olefins may or may not be present at the step of generating a metalalkyl or metal hydride species.

DETAILED DESCRIPTION OF EMBODIMENTS

[0021] The present application discloses a hexadentate ligand (or“ligand”), illustrated by chemical structure I, that is employed in themaking of catalysts for polymerizing and oligomerizing olefins.

[0022] Embodiments of the various types and combinations of “R” groupsare defined below. The hexadentate ligand structure may be identified bysix nitrogens denoted by reference numerals 10, 20, 30, 40, 50, and 60,wherein the ligand may be viewed as consisting of two halves or sides;one side including nitrogen groups 10, 20, and 30, and the other sideincluding nitrogen groups 40, 50, and 60. The two halves are connectedby a structural bridge Y₁. When producing a metal complex from thehexadentate ligand, the ligand is reacted with the salt of a transitionmetal. A coordination reaction between the hexadentate ligand ofchemical structure I and a metal salt forms a hexadentate bimetalliccomplex (or “complex”), such as the one illustrated by chemicalstructure III, which includes two different sites 70 and 80 where themetal salt may coordinate with the ligand. The hexadentate bimetalliccomplex of chemical structure III is a precursor to the catalyst forpolymerizing and oligomerizing olefins.

[0023] In an embodiment, the components of the hexadentate ligand ofstructure I and hexadentate bimetallic complex of structure III, labeledas R₁, R₂, R₃, R₄, R₅, W, Y₁, Z, M, and X_(n) are as follows:

[0024] R₁, R₂, and R₃ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, or an inert functional group, as defined below;

[0025] R₄ and R₅ are each independently hydrogen, hydrocarbyl, an inertfunctional group, or substituted hydrocarbyl;

[0026] Y₁ is a structural bridge between the two halves of the ligandand may be a bond between nitrogen group 30 and nitrogen group 40; or Y₁is a structural bridge wherein Y₁, W, and Z are each independentlyhydrogen, hydrocarbyl, an inert functional group, or substitutedhydrocarbyl including from about 0 to about 30 carbon atoms;

[0027] M₁ and M₂ are metal atoms that may be independently selected fromthe group consisting of cobalt, iron, chromium, and vanadium;

[0028] each X may be an anion, such as a halide or acetyl acetonate, sothat the total number of negative charges on X is equal to the oxidationstate of M₁ or M₂; and

[0029] n is 1, 2, or 3, so that the total number of negative charges onX is equal to the oxidation state of M₁ or M₂.

[0030] In an embodiment of the ligand and complex of structures I andIII, R₁, R₂, R₃, R₄, and R₅ are defined as above; and W, Y₁, and Z areselected such that an activated transition metal complex of the ligand,in the presence of one or more monomers under suitable polymerizationconditions, results in a polymerization product having greater thanabout 50 weight percent oligomers having from about 4 to about 30 carbonatoms. In another embodiment, each half of the hexadentate ligand ofchemical structure I and each half of the hexadentate complex ofchemical structure III is a mirror image of the other. The two halves,one denoted by nitrogen groups 10, 20, and 30, and the other denoted bynitrogen groups 40, 50, and 60, are divided by a mirror plane thatpasses through Y₁. In yet other embodiments of the ligand of structure Iand complex of structure II, the structural bridge Y₁ may becyclohexane.

[0031] In an embodiment of the hexadentate ligand illustrated bystructure I, the groups W, Y₁, and Z are selected to produce thehexadentate ligand illustrated by chemical structure II:

[0032] When preparing a catalyst for olefin polymerization oroligomerization, the hexadentate ligand illustrated by structure II isreacted with a metal salt such that a coordination reaction results inthe hexadentate bimetallic complex of structure IV:

[0033] The groups R_(A), R_(B), R_(C), and R_(D) are ortho to theamines. In an embodiment of the hexadentate ligand II and complex IV,the following pendant groups are defined:

[0034] R₁, R₂, and R₃ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, or an inert functional group, as defined below;

[0035] R₄ and R₅ are each independently hydrogen, hydrocarbyl, an inertfunctional group, or substituted hydrocarbyl;

[0036] R₆, R₇, R₈, R₉, and R₁₀ are each independently hydrogen,hydrocarbyl, an inert functional group, or substituted hydrocarbyl, asdefined below;

[0037] R_(A), R_(B), R_(C), and R_(D) are independently selected fromhydrogen, fluorine, an inert functional group, a primary carbon group, asecondary carbon group, or a tertiary carbon group;

[0038] M₁ and M₂ are metal atoms that may be independently selected fromthe group consisting of cobalt, iron, chromium, and vanadium;

[0039] each X may be an anion such as a halide or acetyl acetonate, sothat the total number of negative charges on X is equal to the oxidationstate of M₁ or M₂;

[0040] n is 1, 2, or 3, so that the total number of negative charges onX is equal to the oxidation state of M₁ or M₂;

[0041] Y₂ is generally a structural bridge between two halves of thestructure, and more particularly may be a bond between rings 120 and130, a hydrocarbyl group including from about 0 to about 20 carbonatoms, methylene (CH₂), ethylene (C₂H₄), or an inert functional group;and

[0042] any two of R_(A), R₆, R₇, R_(B), R_(C), R₈, R₉, R₁₀, R_(D), andany portion of Y₂, vicinal to one another, taken together may form aring.

[0043] In another embodiment of the hexadentate ligand II and complexIV, the pendant groups are as defined above, with the exception that:

[0044] when R_(A) is a primary carbon group, then none, one, or two ofR_(B), R_(C), and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(B), R_(C), and R_(D) are hydrogen or fluorine; or

[0045] when R_(A) is a secondary carbon group, then none, one, or two ofR_(B), R_(C) and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(B), R_(C), and R_(D) are hydrogen or fluorine; or

[0046] when R_(A) is a tertiary carbon group, then none or one of R_(B),R_(C), and R_(D) are tertiary, phenyl, or substituted phenyl, and theremainder are hydrogen or fluorine; and

[0047] when R_(C) is a primary carbon group, then none, one, or two ofR_(A), R_(B), and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine; or

[0048] when R_(C) is a secondary carbon group, then none, one, or two ofR_(A), R_(B) and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine; or

[0049] when R_(C) is a tertiary carbon group, then none or one of R_(A),R_(B), and R_(D) are tertiary, phenyl, or substituted phenyl, and theremainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine.

[0050] In an embodiment, the ligand II and complex IV may be viewed asconsisting of two halves or sides; one side including rings 100, 110,and 120, and the other side including rings 130, 140, and 150. The twohalves are connected by a structural bridge Y₂. In another embodiment,one side of the hexadentate structure identified by rings 100, 110, and120 is a mirror image of the other half of the structure, which isidentified by rings 130, 140, and 150. The two halves or sides of thestructure are divided by a mirror plane, which passes through Y₂. Inanother embodiment, Y₂ connects rings 120 and 130 at their respectivemeta positions and the R₇ groups are located at the respective parapositions.

[0051] Referring to the hexadentate complex IV, other distinctiveembodiments of the ligand and complex may result because the rings 100,120, 130, and 150 may rotate at their chemical bonds. For example, thering 130 may rotate at its bonds 230 and/or 240 such that the resultantligand or complex is not a true mirror image. In the case of a 180degree rotation of the ring 130 along the bonds 230 and 240, asillustrated, the groups R_(A) and R₆ may rotate to the inside of thestructure, and the groups R_(B) and R₇ may rotate to the outside of thestructure. Similarly, ring 100 may rotate along bond 260; ring 120 mayrotate along bonds 210 and 220; ring 130 may rotate along bonds 230 and240; and/or ring 150 may rotate along bond 250.

[0052] In another embodiment of the ligand II and complex IV, R_(A),R_(B), R_(C), and R_(D) are selected such that an activated transitionmetal complex, in the presence of one or more monomers under suitablepolymerization conditions, results in a polymerization product havinggreater than about 50 weight percent oligomers having from about 4 toabout 30 carbon atoms.

[0053] In the following embodiments, unless otherwise specified, allgroups other than the key pendant groups are as defined above. In anembodiment of the ligand II and complex IV, R_(A) and R_(B) arehydrogen; and R_(C) and R_(D) are each independently methyl, ethyl,propyl, or isopropyl. In an embodiment, R_(A) and R_(B) are methyl; andR_(C) and R_(D) are each independently methyl, ethyl, propyl, orisopropyl. In an embodiment, R_(C) and R_(D) are hydrogen; and R_(A) andR_(B) are each independently methyl, ethyl, propyl, or isopropyl. In anembodiment, R_(C) and R_(D) are methyl; and R_(A) and R_(B) are eachindependently methyl, ethyl, propyl, or isopropyl. In an embodiment,R_(A) and R_(D) are hydrogen; and R_(B) and R_(C) are each independentlymethyl, ethyl, propyl, or isopropyl. In an embodiment, R_(A) and R_(D)are methyl; and R_(B) and R_(C) are each independently methyl, ethyl,propyl, or isopropyl.

[0054] In an embodiment of a hexadentate bimetallic complex III or IV,pendant groups may be as defined above, except that both M₁ and M₂ arecobalt. In another embodiment, both M₁ and M₂ are iron. In anotherembodiment, one of the metal atoms, M₁ or M₂, is iron, and the other iscobalt. In another embodiment, selection of M₁ and M₂ affects selectionof R_(A), R_(B), R_(C), R_(D), W, Y₁, and Z.

[0055] In an embodiment of a hexadentate bimetallic complex III or IV,including pendant groups as defined above, an activated complex resultsin an alpha olefin product having greater than about 80 percent 1-alkenecontent.

[0056] In an embodiment of a complex IV, pendant groups may be asdefined above, with the following exceptions:

[0057] R₁, R₂, and R₃ are hydrogen;

[0058] R₄ and R₅ are methyl or hydrogen;

[0059] R₆, R₇, R₈, R₉, and R₁₀ are hydrogen; and

[0060] R_(A), R_(B), R_(C), and R_(D) are each independently methyl,ethyl, propyl, or isopropyl.

[0061] In the following embodiments of a complex IV, pendant groups maybe as defined above, except that M₁ and M₂ are iron, and R₄ and R₅ aremethyl. In an embodiment, R_(A) and R_(B) are hydrogen, and R_(C) andR_(D) are methyl. In an embodiment, R_(A) and R_(B) are methyl, andR_(C) and R_(D) are hydrogen. In another embodiment, R_(A) and R_(C) aremethyl, and R_(B) and R_(D) are hydrogen.

[0062] For purposes of this application, a hydrocarbyl group is a groupcontaining only carbon and hydrogen. If not otherwise stated, it ispreferred that hydrocarbyl groups herein contain 1 to about 30 carbonatoms. The terms “hydrocarbyl” and “alkyl” are equivalent, and may beused interchangeably.

[0063] For purposes of this application, a substituted hydrocarbyl is ahydrocarbyl group which contains one or more substituent groups whichare inert under the process conditions to which the compound containingthese groups is subjected. The substituent groups also do notsubstantially interfere with the process. If not otherwise stated, it ispreferred that substituted hydrocarbyl groups herein contain 1 to about30 carbon atoms. Included in the meaning of “substituted” areheteroaromatic rings.

[0064] For purposes of this application, an inert functional group is agroup, other than hydrocarbyl or substituted hydrocarbyl, which does notsubstantially interfere with any process described herein where thecompound in which it is present takes part. Examples of inert functionalgroups include halo (fluoro, chloro, bromo and iodo), or ethers such as—OR₁₈ wherein R₁₈ is hydrocarbyl or substituted hydrocarbyl. In cases inwhich the functional group may be near a metal atom, such as R₄, R₅, R₈,R_(B), R_(C), and R_(D) the functional group should not coordinate tothe metal atom more strongly than the groups in compounds containing R₄,R₅, R₈, R_(B), R_(C) and R_(D) which are shown as coordinating to themetal atom, that is they should not displace the desired coordinatinggroup.

[0065] For purposes of this application, a primary carbon group includesa group of the formula —CH₂—, wherein the free valence is to any otheratom (the bond represented by the hyphen is to the benzene ring to whichthe primary carbon group is attached). Thus, the free valence may bebonded to a hydrogen atom, halogen atom, carbon atom, oxygen atom,sulfur atom, etc. In other words, the free valence may be to hydrogen,hydrocarbyl, substituted hydrocarbyl or a functional group. Examples ofprimary carbon groups include —CH₃, —CH₂ CH(CH₃)₂, —CH₂ Cl, —CH₂C₆H₅,and —CH₂OCH₃.

[0066] For purposes of this application, a secondary carbon groupincludes a group of the formula —CH═, wherein the free valences are toany other atoms (the bond represented by the hyphen is to the benzenering to which the secondary carbon group is attached). Thus, the freevalences may be bonded to a hydrogen atom, halogen atom, carbon atom,oxygen atom, sulfur atom, etc. In other words, the free valences may beto hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group.Specific examples of secondary carbon groups include —CH(CH₃)₂, —CHCl₂,—CH(C₆H₅)₂, cyclohexyl, —CH(CH₃)OCH₃, and —CH═CHCH₃.

[0067] For purposes of this application, a tertiary carbon groupincludes a group of the formula —C≡, wherein the free valences are toany other atoms. Thus, the free valences may be bonded to a hydrogenatom, halogen atom, carbon atom, oxygen atom, sulfur atom, etc. In otherwords, the free valences may be to hydrogen, hydrocarbyl, substitutedhydrocarbyl or a functional group. Examples of tertiary carbon groupsinclude: —C(CH₃)₃, —C(C₆H₅)₃, —CCl₃, —C(CH₃)₂OCH₃, —C≡CH, —C(CH₃)CH═CH₂,C₆H₅, CF₃, and 1-adamantyl.

[0068] In an embodiment, a method for producing a hexadentate bimetalliccomplex is provided. The method comprises mixing a pyridine compoundhaving chemical structure V:

[0069] with a substituted arylene diamine having chemical structure VI:

[0070] and a substituted aryl amine having chemical structure VII:

[0071] The compounds having chemical structures V, VI, and VII may bemixed in a suitable solvent, as those are commonly known in the art. Inan embodiment, the hexadentate ligand and bimetallic complex may be madeup of the compounds having chemical structures V, VI, and VII in thefollowing ratios: 2 parts chemical structure V, 1 part chemicalstructure VI, and 2 parts chemical structure VII. In an embodiment, therelative amounts of the compounds and order of mixing the compounds maybe selected in order to maximize the yield of the hexadentate ligand ofstructure II. Subsequently, a metal salt of the form MX_(n), as definedabove, may be added to the mixture forming a hexadentate bimetalliccomplex having chemical structure III or IV. In an embodiment, thependant groups of complex III or IV formed by the above method may bedefined as follows:

[0072] R₁, R₂, and R₃ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, or an inert functional group, as defined below;

[0073] R₄ and R₅ are each independently hydrogen, hydrocarbyl, an inertfunctional group, or substituted hydrocarbyl;

[0074] R₆, R₇, R₈, R₉, and R₁₀ are each independently hydrogen,hydrocarbyl, an inert functional group, or substituted hydrocarbyl, asdefined below;

[0075] R_(A), R_(B), R_(C), and R_(D) are independently selected fromhydrogen, fluorine, an inert functional group, a primary carbon group, asecondary carbon group, or a tertiary carbon group;

[0076] M₁ and M₂ are metal atoms that may be independently selected fromthe group consisting of cobalt, iron, chromium, and vanadium;

[0077] each X may be an anion such as a halide or acetyl acetonate, sothat the total number of negative charges on X is equal to the oxidationstate of M₁ or M₂;

[0078] n is 1, 2, or 3, so that the total number of negative charges onX is equal to the oxidation state of M₁ or M₂;

[0079] Y₂ is generally a structural bridge between two halves of thestructure, and more particularly may be a bond between rings 120 and130, a hydrocarbyl group including from about 0 to about 20 carbonatoms, methylene (CH₂), ethylene (C₂H₄), or an inert functional group;and

[0080] any two of R_(A), R₆, R₇, R_(B), R_(C), R₈, R₉, R₁₀, R_(D), andany portion of Y₂, vicinal to one another, taken together may form aring.

[0081] In an embodiment of the above method, a hexadentate ligand havingchemical structure I or II is formed as an intermediate that may beinvolved in a coordination reaction to produce a hexadentate bimetalliccomplex having chemical structure III or IV. In another embodiment ofthe above method, a hexadentate ligand having chemical structure II isformed as an intermediate, wherein ligand purity is at least about 90percent when measured by nuclear magnetic resonance spectroscopy (NMR).In another embodiment, the two halves of the hexadentate ligand andcomplex formed by the above method are divided by a mirror plane. Inanother embodiment, the pendant groups are as defined in the abovemethod, except that:

[0082] M1 and M2 are iron;

[0083] when R_(A) is a primary carbon group, then none, one, or two ofR_(B), R_(C), and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(B), R_(C), and R_(D) are hydrogen or fluorine; or

[0084] when R_(A) is a secondary carbon group, then none, one, or two ofR_(B), R_(C) and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(B), R_(C), and R_(D) are hydrogen or fluorine; or

[0085] when R_(A) is a tertiary carbon group, then none or one of R_(B),R_(C), and R_(D) are tertiary, phenyl, or substituted phenyl, and theremainder are hydrogen or fluorine; and

[0086] when R_(C) is a primary carbon group, then none, one, or two ofR_(A), R_(B), and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine; or

[0087] when R_(C) is a secondary carbon group, then none, one, or two ofR_(A), R_(B) and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine; or

[0088] when R_(C) is a tertiary carbon group, then none or one of R_(A),R_(B), and R_(D) are tertiary, phenyl, or substituted phenyl, and theremainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine.

[0089] In another embodiment, the order of mixing of the arylene diamineand the substituted aryl amine may be dictated by the hexadentatebimetallic complex desired. In another embodiment, R_(A), R_(B), R_(C),and R_(D) are selected such that an activated transition metal complexof the ligand, in the presence of one or more monomers under suitablepolymerization conditions, results in a polymerization product havinggreater than about 50 weight percent oligomers having from about 4 toabout 30 carbon atoms. In another embodiment, the activated complexformed by the above method produces alpha olefins having greater thanabout 80 percent 1-alkene content. In other embodiments, the pendantgroups (including R, W, X, Y, Z, and M groups) of chemical structures V,VI, and VII may be selected such that the hexadentate bimetalliccomplexes resulting from the above method conform to the variouscombinations defined above for the ligands and complexes having chemicalstructures I, II, III and IV.

[0090] In various embodiments, the above method produces the related anddesirable ligands and complexes of Table 1: NUMBER STRUCTURE VIII

IX

X

XI

XII

XIII

XIV

[0091] In the chemical structures of Table 1, groups represented bynothing are hydrogen, and groups represented by a single line, brokenline, or bold line are methyl.

[0092] In an embodiment, a method for preparing a polymerizationcatalyst system is provided. The method comprises a coordinationreaction between a hexadentate ligand having chemical structure I or II,and having embodiments as set out previously in this application, and ametal salt. The result of the coordination reaction includes ahexadentate bimetallic complex having chemical structure III or IV, andhaving embodiments as set out previously in this application. The methodfurther comprises generating a metal alkyl or metal hydride species, andcontacting the catalyst system with one or more monomers under suitablereaction conditions to polymerize the monomer.

[0093] In another embodiment of the method for preparing apolymerization catalyst, olefins may or may not be present duringgeneration of a metal alkyl or metal hydride species. In anotherembodiment, the metal hydride or metal alkyl species is generated by aLewis acid or a combination of a Lewis acid and alkylating agent.Examples of Lewis acids include (C₆F₅)₃B or (C₆H₅)₃B. An example of ametal hydride is NaBH₄. In another embodiment, the metal hydride ormetal alkyl species is generated by an alkyl aluminum compound such as,for example, triethylaluminum (TEA). In another embodiment, the metalhydride or metal alkyl species is generated by an alkyl aluminoxane suchas a methyl-aluminoxane (MAO). In another embodiment, the metal hydrideor metal alkyl species is generated by a combination of Lewis acids,alkyl aluminums, or alkyl aluminoxanes.

EXAMPLES Example 1

[0094] 1.00 g (3.57 mmol) of monoketone 5, which is represented bystructure XV:

[0095] 0.34 g (1.42 mmol) of 4,4′-ethylenedi-m-toluidine, and 25 mg ofp-toluenesulfonic acid were added to a flask in a drybox. A stirbar wasadded, followed by addition of 30 ml of anhydrous toluene. The reactionwas stirred while being refluxed for 5 hours under inert atmosphere. Thereaction was allowed to cool, was filtered to remove a very small amountof dark precipitate, and the solvent was then removed in vacuo. Ethanolwas added to the remaining oil, and the resultant solid (426 mg, 39%)was isolated by filtration and identified by ¹H and ¹³C NMR as chemicalstructure VIII (purity 95%).

Example 2

[0096] Chemical structure VIII (150 mg, 0.196 mmol) and iron(II)chloridetetrahydrate (0.372 mmol) were added together in a small flask with astirbar in a drybox. 10 ml of anhydrous THF was added, and the reactionwas allowed to stir for 18 hours. Pentane was added, and the reactionwas filtered and washed with pentane to give 182 mg (95% yield, assumingtwo equivalents of THF per complex molecule) of chemical structure IX.

Example 3

[0097] 4.24 g (15.1 mmol) of monoketone 5, represented by structure XV,and 1.42 g (7.17 mmol) of 4,4′-methylenedianiline were dissolved in 50ml of anhydrous toluene in a drybox. After dissolution of the solids, 3Amolecular sieves were added and the solution was allowed to sit for 18hours. More molecular sieves were then added, followed by the additionof 4 drops of sulfuric acid. The reaction was refluxed for 3 hours,allowed to cool, and then filtered. The solvent was removed in vacuo,and ethanol was added. The flask was placed in a freezer at 0° C.overnight, and 1.04 g (19%) of solid was removed by filtration after 1day and identified by ¹H NMR as chemical structure X (˜95% pure).

Example 4

[0098] 2,6-Diacetylpyridine (10.0 g, 61.0 mmol) and4,4′-methylenebis(2,6-dimethylaniline) (6.24 g, 24.5 mmol) weredissolved in 300 ml of ethanol in an open beaker. 5 drops of acetic acidwere added, and the reaction was allowed to sit at 25° C. for severaldays. Several crops of crystals were collected (12.2 g, 91%), washedwith cold ethanol, and identified by ¹H NMR as chemical structure XII.

Example 5

[0099] Chemical structure XII (2.0 g, 3.67 mmol) and 4-t-butylaniline(1.8 ml, 11.3 mmol) were dissolved in 50 ml of anhydrous toluene in aflask in a drybox. 3A molecular sieves were added, and the solution wasallowed to sit for 3 days. More molecular sieves were added, followed bythe addition of 2 drops of sulfuric acid. The reaction was refluxed for3 hours, allowed to cool, and filtered. The molecular sieves were washedwith ethanol. The solvent was removed by filtration, ethanol was added,and a solid was collected by filtration. This solid was recrystallizedfrom an ethanol cyclohexane mixture and identified by ¹H NMR as chemicalstructure XIII (490 mg, 17% yield, ˜95% purity).

Example 6

[0100] Chemical structure XIII (300 mg, 0.372 mmol) and iron(II)chloridetetrahydrate (148 mg, 0.744 mmol) were added together in a small flaskwith a stirbar in a drybox. 15 ml of anhydrous THF was added, and thereaction was allowed to stir for 18 hours. Pentane was added, and thereaction was filtered and washed with ether and pentane to give 350 mg(78% yield, assuming two equivalents of THF per complex molecule) ofchemical structure XIV.

Example 7

[0101] Under semi-continuous operating conditions, 120 grams ofcyclohexane were pumped into a 1 liter reactor, and the reactor waspressurized with ethylene. Next pumps were used to quickly transfer thefirst hour's amounts of chemical structure XIV and triethylaluminum(TEA) to the reactor. The hourly flow rates were then set for thecatalyst and co-catalyst, and the reaction was allowed to exotherm tothe desired run temperature. The reaction was stopped 150 minutes afterreaching 50° C. The data in the following table represent the lastsample taken before stopping the reaction. Solvent (120 g) CyH CatalystXIV Flowrate (mg/hr) 0.2 Yield (g) 374 lb prod/lb Al 5004 lb prod/lb Fecat (×10³) 509 Al:Fe ratio 2000 K(C20/C18) 0.68 K(C16/C14) 0.69K(C10/C8) 0.69 P ethylene (psig) 500 1-hexene Purity 99.34 C6 % BranchedAlpha Olefins (BAO) 0.17 C6 % Paraffin 0.21 1-octene Purity 99.05 C8 %Branched Alpha Olefins (BAO) 0.29

[0102] The following chart illustrates the catalyst's high selectivityfor ethylene relative to higher olefins:

[0103] While the present invention has been illustrated and described interms of particular apparatus and methods of use, it is apparent thatequivalent techniques and ingredients may be substituted for thoseshown, and other changes can be made within the scope of the presentinvention as defined by the appended claims.

[0104] The particular embodiments disclosed herein are illustrativeonly, as the invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is therefore evident that theparticular embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. Accordingly, the protection sought herein is as set forth inthe claims below.

What we claim as our invention is:
 1. A hexadentate ligand forpolymerization of olefins comprising chemical structure I:

wherein R₁, R₂, and R₃ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, or an inert functional group; R₄ and R₅ areeach independently hydrogen, hydrocarbyl, an inert functional group, orsubstituted hydrocarbyl; and Y₁ is a structural bridge, and W, Y₁, and Zare independently hydrogen, hydrocarbyl, an inert functional group, orsubstituted hydrocarbyl having from about 0 to about 30 carbon atoms. 2.The ligand of claim 1 wherein W, Y₁, and Z are selected such that anactivated transition metal complex of the ligand results in greater thanabout 50 weight percent of the polymerization product comprisingoligomers having from about 4 to about 30 carbon atoms.
 3. The ligand ofclaim 1 further comprising a mirror plane.
 4. The ligand of claim 1wherein Y₁ is cyclohexane.
 5. The ligand of claim 1 wherein W, Y₁, and Zare selected to produce chemical structure II:

wherein R₆, R₇, R₈, R₉, and R₁₀ are each independently hydrogen,hydrocarbyl, an inert functional group, or substituted hydrocarbyl;R_(A), R_(B), R_(C), and R_(D) are each independently hydrogen,fluorine, an inert functional group, a primary carbon group, a secondarycarbon group, or a tertiary carbon group; Y₂ is a structural bridgebetween two halves of the structure, and more particularly may be abond, a hydrocarbyl group comprising from about 0 to about 20 carbonatoms, methylene (CH₂), ethylene (C₂H₄), or an inert functional group;and any two of R_(A), R₆, R₇, R_(B), R_(C), R₈, R₉, R₁₀, and R_(D), orany portion of Y₂, vicinal to one another, taken together may form aring.
 6. The ligand of claim 5 wherein: when R_(A) is a primary carbongroup, then none, one, or two of R_(B), R_(C), and R_(D) are primarycarbon groups, secondary carbon groups, phenyl, substituted phenyl, orinert functional groups, and the remainder of R_(B), R_(C), and R_(D)are hydrogen or fluorine; when R_(A) is a secondary carbon group, thennone, one, or two of R_(B), R_(C) and R_(D) are primary carbon groups,secondary carbon groups, phenyl, substituted phenyl, or inert functionalgroups, and the remainder of R_(B), R_(C), and R_(D) are hydrogen orfluorine; when R_(A) is a tertiary carbon group, then none or one ofR_(B), R_(C), and R_(D) are tertiary, phenyl, or substituted phenyl, andthe remainder are hydrogen or fluorine; when R_(C) is a primary carbongroup, then none, one, or two of R_(A), R_(B), and R_(D) are primarycarbon groups, secondary carbon groups, phenyl, substituted phenyl, orinert functional groups, and the remainder of R_(A), R_(B), and R_(D)are hydrogen or fluorine; when R_(C) is a secondary carbon group, thennone, one, or two of R_(A), R_(B) and R_(D) are primary carbon groups,secondary carbon groups, phenyl, substituted phenyl, or inert functionalgroups, and the remainder of R_(A), R_(B), and R_(D) are hydrogen orfluorine; and when R_(C) is a tertiary carbon group, then none or one ofR_(A), R_(B), and R_(D) are tertiary, phenyl, or substituted phenyl, andthe remainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine. 7.The ligand of claim 5 further comprising a mirror plane.
 8. The ligandof claim 5 wherein Y₂ connects rings at their respective meta positionsand R₇ is located at the respective para positions.
 9. The ligand ofclaim 5 wherein R_(A), R_(B), R_(C), and R_(D) are selected such that anactivated transition metal complex of the ligand results in greater thanabout 50 weight percent of the polymerization product comprisingoligomers having from about 4 to about 30 carbon atoms.
 10. The ligandof claim 5 wherein R_(A) and R_(B) are hydrogen; and R_(C) and R_(D) areindependently methyl, ethyl, propyl, or isopropyl.
 11. The ligand ofclaim 10 wherein R_(C) and R_(D) are both methyl.
 12. The ligand ofclaim 5 wherein R_(C) and R_(D) are hydrogen; and R_(A) and R_(B) areindependently methyl, ethyl, propyl, or isopropyl.
 13. The ligand ofclaim 12 wherein R_(A) and R_(B) are both methyl.
 14. The ligand ofclaim 5 wherein R_(A) and R_(D) are hydrogen; and R_(B) and R_(C) areindependently methyl, ethyl, propyl, or isopropyl.
 15. The ligand ofclaim 14 wherein R_(B) and R_(C) are both methyl.
 16. The ligand ofclaim 5 wherein Y₂ is a bond, methylene (CH₂), or ethylene (C₂H₄). 17.The ligand of claim 5 having chemical structure VIII:


18. The ligand of claim 5 having chemical structure X:


19. The ligand of claim 5 having chemical structure XII:


20. The ligand of claim 5 having chemical structure XIII:


21. The hexadentate ligand of claim 1 reacted to form a hexadentatebimetallic complex having chemical structure III:

wherein M₁ and M₂ are metal atoms that are independently selected from agroup comprising cobalt, iron, chromium, and vanadium; each X is ananion; and n is 1, 2, or 3, so that the total number of negative chargeson X is equal to the oxidation state of M₁ or M₂.
 22. The complex ofclaim 21 wherein M₁ and M₂ are iron.
 23. The complex of claim 21 whereinsaid complex comprises a mirror plane.
 24. The complex of claim 21wherein M₁ and M₂ are cobalt.
 25. The complex of claim 21 wherein X, Y₁,and Z are selected such that greater than about 50 weight percent of thepolymerization product made by an activated complex comprises oligomershaving from about 4 to about 30 carbon atoms.
 26. The complex of claim21 wherein the activated complex produces alpha olefins of at leastabout 80 percent 1-alkene content.
 27. The complex of claim 21 whereinselection of M₁ and M₂ affects selection of X, Y₁, and Z.
 28. Thecomplex of claim 21 wherein X is a halide or acetyl acetonate.
 29. Thecomplex of claim 21 wherein X, Y₁, and Z are selected to producechemical structure IV:

wherein R₆, R₇, R₈, R₉, and R₁₀ are each independently hydrogen,hydrocarbyl, an inert functional group, or substituted hydrocarbyl;R_(A), R_(B), R_(C), and R_(D) are each independently hydrogen,fluorine, an inert functional group, a primary carbon group, a secondarycarbon group, or a tertiary carbon group; and Y₂ is a structural bridgebetween two halves of the structure, and more particularly may be abond, a hydrocarbyl group comprising from about 0 to about 20 carbonatoms, methylene (CH₂), ethylene (C₂H₄), or an inert functional group;and any two of R_(A), R₆, R₇, R_(B), R_(C), R₈, R₉, R₁₀, and R_(D), orany portion of Y₂, vicinal to one another, taken together may form aring.
 30. The complex of claim 29 wherein: when R_(A) is a primarycarbon group, then none, one, or two of R_(B), R_(C), and R_(D) areprimary carbon groups, secondary carbon groups, phenyl, substitutedphenyl, or inert functional groups, and the remainder of R_(B), R_(C),and R_(D) are hydrogen or fluorine; or when R_(A) is a secondary carbongroup, then none, one, or two of R_(B), R_(C) and R_(D) are primarycarbon groups, secondary carbon groups, phenyl, substituted phenyl, orinert functional groups, and the remainder of R_(B), R_(C), and R_(D)are hydrogen or fluorine; or when R_(A) is a tertiary carbon group, thennone or one of R_(B), R_(C), and R_(D) are tertiary, phenyl, orsubstituted phenyl, and the remainder are hydrogen or fluorine; and whenR_(C) is a primary carbon group, then none, one, or two of R_(A), R_(B),and R_(D) are primary carbon groups, secondary carbon groups, phenyl,substituted phenyl, or inert functional groups, and the remainder ofR_(A), R_(B), and R_(D) are hydrogen or fluorine; or when R_(C) is asecondary carbon group, then none, one, or two of R_(A), R_(B) and R_(D)are primary carbon groups, secondary carbon groups, phenyl, substitutedphenyl, or inert functional groups, and the remainder of R_(A), R_(B),and R_(D) are hydrogen or fluorine; or when R_(C) is a tertiary carbongroup, then none or one of R_(A), R_(B), and R_(D) are tertiary, phenyl,or substituted phenyl, and the remainder of R_(A), R_(B), and R_(D) arehydrogen or fluorine.
 31. The complex of claim 29 wherein M₁ and M₂ areiron.
 32. The complex of claim 29 wherein said complex comprises amirror plane.
 33. The complex of claim 29 wherein M₁ and M₂ are cobalt.34. The complex of claim 29 wherein R_(A), R_(B), R_(C), and R_(D) areselected such that greater than about 50 weight percent of thepolymerization product made by an activated complex comprises oligomershaving from about 4 to about 30 carbon atoms.
 35. The complex of claim29 wherein the activated complex produces alpha olefins of at leastabout 80 percent 1-alkene content.
 36. The complex of claim 29 whereinselection of M₁ and M₂ affects selection of R_(A), R_(B), R_(C), andR_(D).
 37. The complex of claim 29 wherein X is a halide or acetylacetonate.
 38. The complex of claim 29 wherein R₁, R₂, and R₃ arehydrogen; R₄ and R₅ are methyl or hydrogen; R₆, R₇, R₈, R₉ and R₁₀ arehydrogen; and R_(A), R_(B), R_(C), and R_(D) are each independentlymethyl, ethyl, propyl, or isopropyl.
 39. The complex of claim 29 whereinR_(A) and R_(B) are hydrogen; and R_(C) and R_(D) are independentlymethyl, ethyl, propyl, or isopropyl.
 40. The complex of claim 39 whereinR_(C) and R_(D) are both methyl.
 41. The complex of claim 29 whereinR_(C) and R_(D) are hydrogen; and R_(A) and R_(B) are independentlymethyl, ethyl, propyl, or isopropyl.
 42. The complex of claim 41 whereinR_(A) and R_(B) are both methyl.
 43. The complex of claim 29 whereinR_(A) and R_(D) are hydrogen; and R_(B) and R_(C) are independentlymethyl, ethyl, propyl, or isopropyl.
 44. The complex of claim 43 whereinR_(B) and R_(C) are both methyl.
 45. The complex of claim 31 wherein: R₄and R₅ are methyl; R_(A) and R_(B) are hydrogen; and R_(C) and R_(D) aremethyl.
 46. The complex of claim 31 wherein: R₄ and R₅ are methyl; R_(A)and R_(B) are methyl; and R_(C) and R_(D) are hydrogen.
 47. The complexof claim 31 wherein: R₄ and R₅ are methyl; R_(A) and R_(C) are methyl;and R_(B) and R_(D) are hydrogen.
 48. The complex of claim 29 wherein Y₂is a bond, methylene (CH₂), or ethylene (C₂H₄).
 49. The complex of claim29 having chemical structure IX:


50. The complex of claim 29 having chemical structure XI:


51. The complex of claim 29 having chemical structure XIV:


52. The complex of claim 21 further comprising a polymerization catalystsystem, the polymerization catalyst system comprising a metal alkyl ormetal hydride species.
 53. The complex of claim 52 wherein the metalalkyl or metal hydride species is generated by a compound selected fromthe group consisting of one or more Lewis acids; a combination of one ormore Lewis acids and one ore more alkylating agents; one or more alkylaluminum compounds; one or more alkyl aluminoxanes; methyl aluminoxane;tri-ethyl aluminum; and combinations thereof.
 54. The complex of claim29 further comprising a polymerization catalyst system, thepolymerization catalyst system comprising a metal alkyl or metal hydridespecies.
 55. The complex of claim 54 wherein the metal alkyl or metalhydride species is generated by a compound selected from the groupconsisting of one or more Lewis acids; a combination of one or moreLewis acids and one ore more alkylating agents; one or more alkylaluminum compounds; one or more alkyl aluminoxanes; methyl aluminoxane;tri-ethyl aluminum; and combinations thereof.
 56. The complex of claim49 further comprising a polymerization catalyst system, thepolymerization catalyst system comprising a metal alkyl or metal hydridespecies.
 57. The complex of claim 56 wherein the metal alkyl or metalhydride species is generated by a compound selected from the groupconsisting of one or more Lewis acids; a combination of one or moreLewis acids and one ore more alkylating agents; one or more alkylaluminum compounds; one or more alkyl aluminoxanes; methyl aluminoxane;tri-ethyl aluminum; and combinations thereof.
 58. The complex of claim50 further comprising a polymerization catalyst system, thepolymerization catalyst system comprising a metal alkyl or metal hydridespecies.
 59. The complex of claim 58 wherein the metal alkyl or metalhydride species is generated by a compound selected from the groupconsisting of one or more Lewis acids; a combination of one or moreLewis acids and one ore more alkylating agents; one or more alkylaluminum compounds; one or more alkyl aluminoxanes; methyl aluminoxane;tri-ethyl aluminum; and combinations thereof.
 60. The complex of claim51 further comprising a polymerization catalyst system, thepolymerization catalyst system comprising a metal alkyl or metal hydridespecies.
 61. The complex of claim 60 wherein the metal alkyl or metalhydride species is generated by a compound selected from the groupconsisting of one or more Lewis acids; a combination of one or moreLewis acids and one ore more alkylating agents; one or more alkylaluminum compounds; one or more alkyl aluminoxanes; methyl aluminoxane;tri-ethyl aluminum; and combinations thereof.
 62. A method for producinga hexadentate bimetallic complex having chemical structure IV:

comprising: mixing a pyridine compound having chemical structure V:

with a substituted arylene diamine having chemical structure VI:

and a substituted aryl amine having chemical structure VII:

in a suitable solvent; and adding at least one metal salt of the formulaMX_(n); wherein R₁, R₂, and R₃ are each independently hydrogen,hydrocarbyl, substituted hydrocarbyl, or an inert functional group; R₄and R₅ are each independently hydrogen, hydrocarbyl, an inert functionalgroup, or substituted hydrocarbyl; R₆, R₇, R₈, R₉, and R₁₀ are eachindependently hydrogen, hydrocarbyl, an inert functional group, orsubstituted hydrocarbyl; R_(A), R_(B), R_(C), and R_(D) are eachindependently hydrogen, fluorine, an inert functional group, a primarycarbon group, a secondary carbon group, or a tertiary carbon group; Y₂is a structural bridge between two halves of the structure, and moreparticularly may be a bond, a hydrocarbyl group comprising from about 0to about 20 carbon atoms, methylene (CH₂), ethylene (C₂H₄), or an inertfunctional group; any two of R_(A), R₆, R₇, R_(B), R_(C), R₈, R₉, R₁₀,and R_(D), or any portion of Y₂, vicinal to one another, taken togethermay form a ring; M₁ and M₂ are independently selected metal atoms thatare selected from a group comprising cobalt, iron, chromium, andvanadium; each X is an anion; and n is 1, 2, or 3, so that the totalnumber of negative charges on X is equal to the oxidation state of M₁ orM₂.
 63. The method of claim 62 wherein: when R_(A) is a primary carbongroup, then none, one, or two of R_(B), R_(C), and R_(D) are primarycarbon groups, secondary carbon groups, phenyl, substituted phenyl, orinert functional groups, and the remainder of R_(B), R_(C), and R_(D)are hydrogen or fluorine; when R_(A) is a secondary carbon group, thennone, one, or two of R_(B), R_(C) and R_(D) are primary carbon groups,secondary carbon groups, phenyl, substituted phenyl, or inert functionalgroups, and the remainder of R_(B), R_(C), and R_(D) are hydrogen orfluorine; when R_(A) is a tertiary carbon group, then none or one ofR_(B), R_(C), and R_(D) are tertiary, phenyl, or substituted phenyl, andthe remainder are hydrogen or fluorine; when R_(C) is a primary carbongroup, then none, one, or two of R_(A), R_(B), and R_(D) are primarycarbon groups, secondary carbon groups, phenyl, substituted phenyl, orinert functional groups, and the remainder of R_(A), R_(B), and R_(D)are hydrogen or fluorine; when R_(C) is a secondary carbon group, thennone, one, or two of R_(A), R_(B) and R_(D) are primary carbon groups,secondary carbon groups, phenyl, substituted phenyl, or inert functionalgroups, and the remainder of R_(A), R_(B), and R_(D) are hydrogen orfluorine; and when R_(C) is a tertiary carbon group, then none or one ofR_(A), R_(B), and R_(D) are tertiary, phenyl, or substituted phenyl, andthe remainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine. 64.The method of claim 63 wherein M₁ and M₂ are iron.
 65. The method ofclaim 62 further comprising forming an intermediate hexadentate ligandhaving chemical structure II:


66. The method of claim 65 wherein said intermediate hexadentate ligandhas a purity of at least about 90 percent when measured by NMR.
 67. Themethod of claim 65 wherein said hexadentate ligand and hexadentatebimetallic complex each comprise a mirror plane.
 68. The method of claim62 wherein R_(A), R_(B), R_(C), and R_(D) are selected such that theactivated complex results in a polymerization product comprising greaterthan about 50 weight percent oligomers having from about 4 to about 30carbon atoms.
 69. The method of claim 62 wherein the order of mixingsaid pyridine compound with said substituted arylene diamine and saidsubstituted aryl amine in said suitable solvent is dictated by thecomplex desired.
 70. The method of claim 62 wherein X is a halide oracetyl acetonate.
 71. The method of claim 62 wherein said methodproduces a complex having chemical structure IX:


72. The method of claim 71 wherein an intermediate ligand havingchemical structure VIII is formed:


73. The method of claim 62 wherein said method produces a complex havingchemical structure XI:


74. The method of claim 73 wherein an intermediate ligand havingchemical structure X is formed:


75. The method of claim 62 wherein said method produces a complex havingchemical structure XIV:


76. The method of claim 75 wherein said an intermediate ligand havingchemical structure XII is formed:


77. The method of claim 75 wherein an intermediate ligand havingchemical structure XIII is formed:


78. A method for preparing a polymerization catalyst comprising:executing a coordination reaction between a hexadentate ligand havingchemical structure II:

and a metal salt of the formula MX_(n) to form a hexadentate bimetalliccomplex having chemical structure IV:

wherein R₁, R₂, and R₃ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, or an inert functional group; R₄ and R₅ areeach independently hydrogen, hydrocarbyl, an inert functional group, orsubstituted hydrocarbyl; R₆, R₇, R₈, R₉, and R₁₀ are each independentlyhydrogen, hydrocarbyl, an inert functional group, or substitutedhydrocarbyl; R_(A), R_(B), R_(C), and R_(D) are each independentlyhydrogen, fluorine, an inert functional group, a primary carbon group, asecondary carbon group, or a tertiary carbon group; Y₂ is a structuralbridge between two halves of the structure, and more particularly may bea bond, a hydrocarbyl group comprising from about 0 to about 20 carbonatoms, methylene (CH₂), ethylene (C₂H₄), or an inert functional group;any two of R_(A), R₆, R₇, R_(B), R_(C), R₈, R₉, R₁₀, and R_(D), or anyportion of Y₂, vicinal to one another, taken together may form a ring;M₁ and M₂ are independently selected metal atoms that are selected froma group comprising cobalt, iron, chromium, and vanadium; each X is ananion; n is 1, 2, or 3, so that the total number of negative charges onX is equal to the oxidation state of M₁ or M₂; and wherein olefins mayor may not be present when generating a metal alkyl or metal hydridespecies.
 79. The method of claim 78 wherein: M₁ and M₂ are both iron;when R_(A) is a primary carbon group, then none, one, or two of R_(B),R_(C), and R_(D) are primary carbon groups, secondary carbon groups,phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(B), R_(C), and R_(D) are hydrogen or fluorine; whenR_(A) is a secondary carbon group, then none, one, or two of R_(B),R_(C) and R_(D) are primary carbon groups, secondary carbon groups,phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(B), R_(C), and R_(D) are hydrogen or fluorine; whenR_(A) is a tertiary carbon group, then none or one of R_(B), R_(C), andR_(D) are tertiary, phenyl, or substituted phenyl, and the remainder arehydrogen or fluorine; when R_(C) is a primary carbon group, then none,one, or two of R_(A), R_(B), and R_(D) are primary carbon groups,secondary carbon groups, phenyl, substituted phenyl, or inert functionalgroups, and the remainder of R_(A), R_(B), and R_(D) are hydrogen orfluorine; when R_(C) is a secondary carbon group, then none, one, or twoof R_(A), R_(B) and R_(D) are primary carbon groups, secondary carbongroups, phenyl, substituted phenyl, or inert functional groups, and theremainder of R_(A), R_(B), and R_(D) are hydrogen or fluorine; and whenR_(C) is a tertiary carbon group, then none or one of R_(A), R_(B), andR_(D) are tertiary, phenyl, or substituted phenyl, and the remainder ofR_(A), R_(B), and R_(D) are hydrogen or fluorine.
 80. The method ofclaim 78 wherein each of said hexadentate ligand and said hexadentatebimetallic complex comprise a mirror plane.
 81. The method of claim 78wherein R_(A), R_(B), R_(C), and R_(D) are selected such that anactivated complex results in greater than about 50 weight percent of thepolymerization product comprises alpha-olefin oligomers having fromabout 4 to about 30 carbon atoms.
 82. The method of claim 78 wherein M₁and M₂ are cobalt.
 83. The method of claim 78 wherein X is a halide oracetyl acetonate.
 84. The method of claim 78 further comprising adding ametal alkyl or metal hydride species.
 85. The method of claim 84 whereinthe metal alkyl or metal hydride species is generated by a compoundselected from the group consisting of one or more Lewis acids; acombination of one or more Lewis acids and one ore more alkylatingagents; one or more alkyl aluminum compounds; one or more alkylaluminoxanes; methyl aluminoxane; tri-ethyl aluminum; and combinationsthereof.
 86. The method of claim 84 further comprising contacting thecatalyst with one or more monomers under suitable reaction conditions topolymerize the monomer.